In recent years, demand for a rear projection is becoming increasingly strong as a suitable display for a monitor for a home theater, a large screen television, or the like. In a transmission screen used for the rear projector, lenticular lenses are in general use. However, a conventional rear projection provided with such lenticular lenses has a problem that the vertical angle of view thereof is small although the lateral angle of view thereof is large (this is, there is a bias in the angles of view).
In order to solve such a problem, an attempt to use a microlens sheet on which a plurality of microlenses are formed so that concave portions or convex portions have optically rotational symmetry has been proposed (for example, see JP-A-2000-131506). The microlens sheet (microlens substrate) as described above has been conventionally manufactured using a so-called 2P method. In the 2P method, a uncured resin is supplied onto a substrate provided with a plurality of concave portions for forming a plurality of microlenses, the supplied resin is pressed and made to adhere closely to the substrate with concave portions by bringing a flat and transparent substrate contact with the resin, and then the resin is cured (for example, see JP-A-2003-279949).
However, in the 2P method as described above, there is a problem that it is difficult to release the cured resin from the substrate with concave portions. Further, such a problem becomes further remarkable in the case where the microlens substrate to be manufactured has a large area. For this reason, there is a possibility that yields become extremely low when manufacturing a large-sized microlens substrate.
Further, in the case where a microlens substrate to be manufactured is one having a large size (for example, a substrate having a diagonal length thereof of 140 cm or more), the problem as described above becomes more remarkable. In addition, the size of the substrate with concave portions used to manufacture a microlens substrate becomes larger, and therefore, there is a problem that the manufacturing facility for the microlens substrate becomes larger further. Moreover, along with rapid size-up of a monitor for a home cheater, a display or the like in recent years, it is required that the substrate with concave portions corresponding to the monitor or the like gets larger, whereby it is necessary to manufacture various types (sizes) of substrates with concave portions corresponding to various sizes of monitor or the like. As a result, a problem that price reduction of a microlens substrate is prevented for this reason happens.